Universal Manufacturing uses a weighted-average process-costing system. All materials are introduced at the start of manufacturing, and conversion costs are incurred evenly throughout the process. The company's beginning and ending work-in-process inventories totaled 10,000 units and 15,000 units, respectively, with the latter units being 2/3 complete at the end of the period. Universal started 30,000 units into production and completed 25,000 units. Manufacturing costs follow.

Beginning work in process: Materials, $60,000; conversion cost, $150,000

Current costs: Materials, $180,000; conversion cost, $480,000

Universal's equivalent-unit cost for conversion cost is:

$13.71.

$18.00.

$21.00.

$25.20.

some other amount.